This invention relates to a rotation damper for damping the rotation of a rotating member such as cassette lid for tape recorder.
Various rotation dampers are used to provide braking force on, for instance, tape cassette holder lids for tape recorders, video cassettes, etc. for preventing the lids from being quickly opened. Such rotation dampers are disclosed, for example, in Japanese Utility Model Publication No. 56-50572 and Japanese Utility Model Application Disclosure Nos. 54-82614, 56-103902 and 56-111403. All of these rotation dampers utilize the frictional force between a rotating member rotated by an input rotational force and a body surrounding or facing the rotating member for damping the rotating force. Therefore, the dampers wear out and lose their braking action after long use. In order to solve the problems of the rotation dampers based on the frictional force, the applicant earlier proposed a rotation damper, in which a rotating member is rotated in or in contact with high viscosity oil such as silicone grease, and which thus provides a braking action based on the resistance offered by the viscosity of the oil, as disclosed in U.S. Pat. No. 4,342,135.
In these rotation dampers, the braking action is provided when a locking mechanism which locks, for instance, the cassette holder lid of a cassette tape recorder (the rotating member) in a closed position, is released by depressing an ejection button or the like. This means that a locking mechanism for holding the lid locked in the closed position must be incorporated, in addition to a damper between the lid and the apparatus body and a spring for biasing the lid in the opening direction, thus increasing the number of components, complexity of assembly and cost of the apparatus.